Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the safety profile (readOnly=false, destructive=false, idempotent=false), lowering the bar. The description still adds non-obvious behavior: confirm=false triggers a dry-run, and the call returns an ad_group_id that downstream tools require. It does not cover auth scopes or rate limits, but the dry-run default is the key behavioral disclosure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose is front-loaded in the first sentence, followed by workflow context and parameter notes. The arrow-chain sentence is dense but each tool it names earns its place by disambiguating the sequencing, and there is no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need no prose explanation, and annotations carry the safety profile. For a create tool with a clear workflow and the two tricky params documented, an agent has everything needed to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0%, so the description must compensate. It explains the two ambiguous params well — cpc_bid as the group's default max CPC in account currency, and confirm=false as dry-run — while customer_id, campaign_id, and name are self-evident from their names, so the remaining gap is minor.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Creates a new AD GROUP inside a Google Ads campaign') and immediately scopes it ('the layer between the campaign and its keywords/ads'). The Google Ads qualifier cleanly distinguishes it from siblings like create_microsoft_ad_group, create_tiktok_adgroup, and create_meta_adset.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly places the tool in an end-to-end workflow (create_search_campaign → create_ad_group → add_keywords → create_responsive_search_ad), naming the sibling tools it depends on and follows. It also gives the 'one per theme' heuristic, so an agent knows both when and how often to call it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.